Continuously variable transmission

ABSTRACT

A continuously variable transmission is disclosed for use in rotationally or linearly powered machines and vehicles. The transmission provides a simple manual shifting method for the user. Further, the practical commercialization of traction roller transmissions requires improvements in the reliability, ease of shifting, function and simplicity of the transmission. The present invention includes a continuously variable transmission that may be employed in connection with any type of machine that is in need of a transmission. For example, the transmission may be used in (i) a motorized vehicle such as an automobile, motorcycle, or watercraft, (ii) a non-motorized vehicle such as a bicycle, tricycle, scooter, exercise equipment or (iii) industrial equipment, such as a drill press, power generating equipment, or textile mill.

RELATED APPLICATIONS

[0001] This application is a continuation of and claims priority to U.S.application Ser. No. 10/134,097 filed on Apr. 25, 2002, which in turnclaims priority from U.S. Provisional Application No. 60/286,803, filedApr. 26, 2001. The entire disclosure of each of those applications ishereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The field of the invention relates generally to transmissions,and more particularly the invention relates to continuously variabletransmissions.

[0004] 2. Description of the Related Art

[0005] The present invention relates to the field of continuouslyvariable transmissions and includes several novel features and inventiveaspects that have been developed and are improvements upon the priorart. In order to provide an infinitely variable transmission, varioustraction roller transmissions in which power is transmitted throughtraction rollers supported in a housing between torque input and outputdisks have been developed. In such transmissions, the traction rollersare mounted on support structures which, when pivoted, cause theengagement of traction rollers with the torque disks in circles ofvarying diameters depending on the desired transmission ratio.

[0006] However, the success of these traditional solutions has beenlimited. For example, in one solution, a driving hub for a vehicle witha variable adjustable transmission ratio is disclosed. This methodteaches the use of two iris plates, one on each side of the tractionrollers, to tilt the axis of rotation of each of the rollers. However,the use of iris plates can be very complicated due to the large numberof parts that are required to adjust the iris plates during transmissionshifting. Another difficulty with this transmission is that it has aguide ring that is configured to be predominantly stationary in relationto each of the rollers. Since the guide ring is stationary, shifting theaxis of rotation of each of the traction rollers is difficult.

[0007] One improvement over this earlier design includes a shaft aboutwhich a driving member and a driven member rotate. The driving memberand driven member are both mounted on the shaft and contact a pluralityof power adjusters disposed equidistantly and radially about the shaft.The power adjusters are in frictional contact with both members andtransmit power from the driving member to the driven member. A supportmember located concentrically over the shaft and between the poweradjusters applies a force to keep the power adjusters separate so as tomake frictional contact against the driving member and the drivenmember. A limitation of this design is the absence of means forgenerating an adequate axial force to keep the driving and drivenmembers in sufficient frictional contact against the power adjusters asthe torque load on the transmission changes. A further limitation ofthis design is the difficulty in shifting that results at high torqueand very low speed situations as well as insufficient means fordisengaging the transmission and coasting.

[0008] Therefore, there is a need for a continuously variabletransmission with an improved power adjuster support and shiftingmechanism, means of applying proper axial thrust to the driving anddriven members for various torque and power loads, and means ofdisengaging and reengaging the clutch for coasting.

SUMMARY OF THE INVENTION

[0009] The systems and methods have several features, no single one ofwhich is solely responsible for its desirable attributes. Withoutlimiting the scope as expressed by the claims that follow, its moreprominent features will now be discussed briefly. After considering thisdiscussion, and particularly after reading the section entitled“Detailed Description of the Preferred Embodiments” one will understandhow the features of the system and methods provide several advantagesover traditional systems and methods.

[0010] In one aspect, a continuously variable transmission is disclosedhaving a longitudinal axis, and a plurality of speed adjusters. Eachspeed adjuster has a tiltable axis of rotation is located radiallyoutward from the longitudinal axis. Also provided are a drive disk thatis annularly rotatable about the longitudinal axis and also contacts afirst point on each of the speed adjusters and a support member that isalso annularly rotatable about the longitudinal axis. A bearing disk isprovided that is annularly rotatable about the longitudinal axis aswell, and at least two axial force generators. The axial forcegenerators are located between the drive disk and the bearing disk andeach axial force generator is configured to apply an axial force to thedrive disk.

[0011] In another aspect, a bearing disk annularly rotatable about thelongitudinal axis is disclosed along with a disengagement mechanism. Thedisengagement mechanism can be positioned between the bearing disk andthe drive disk and is adapted to cause the drive disk to disengage thedrive disk from the speed adjusters.

[0012] In yet another aspect, an output disk or rotatable hub shell isdisclosed along with a bearing disk that is annularly rotatable aboutthe longitudinal axis of the transmission. A support member is includedthat is annularly rotatable about the longitudinal axis as well, and isadapted to move toward whichever of the drive disk or the output disk isrotating more slowly.

[0013] In still another aspect, a linkage subassembly having a hook isdisclosed, wherein the hook is attached to either the drive disk or thebearing disk. Included is a latch attached to either the drive disk orand the bearing disk.

[0014] In another aspect, a plurality of spindles having two ends isdisclosed, wherein one spindle is positioned in the bore of each speedadjuster and a plurality of spindle supports having a platform end andspindle end is provided. Each spindle support is operably engaged withone of the two ends of one of the spindles. Also provided is a pluralityof spindle support wheels, wherein at least one spindle support wheel isprovided for each spindle support. Included are annular first and secondstationary supports each having a first side facing the speed adjustersand a second side facing away from the speed adjusters. Each of thefirst and second stationary supports have a concave surface on the firstside and the first stationary support is located adjacent to the drivedisk and the second stationary support is located adjacent to the drivendisk.

[0015] Also disclosed is a continuously variable transmission having acoiled spring that is positioned between the bearing disk and the drivedisk.

[0016] In another aspect, a transmission shifting mechanism is disclosedcomprising a rod, a worm screw having a set of external threads, ashifting tube having a set of internal threads, wherein a rotation ofthe shifting tube causes a change in the transmission ratio, a sleevehaving a set of internal threads, and a split shaft having a threadedend.

[0017] In yet another aspect, a remote transmission shifter is disclosedcomprising a rotatable handlegrip, a tether having a first end and asecond end, wherein the first end is engaged with the handlegrip and thesecond end is engaged with the shifting tube. The handlegrip is adaptedto apply tension to the tether, and the tether is adapted to actuate theshifting tube upon application of tension.

[0018] These and other improvements will become apparent to thoseskilled in the art as they read the following detailed description andview the enclosed figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a cutaway side view of an embodiment of thetransmission.

[0020]FIG. 2 is a partial end cross-sectional view taken on line II-IIof FIG. 1.

[0021]FIG. 3 is a perspective view of a split shaft and two stationarysupports of the transmission of FIG. 1.

[0022]FIG. 4 is a schematic cutaway side view of the transmission ofFIG. 1 shifted into low.

[0023]FIG. 5 is a schematic cutaway side view of the transmission ofFIG. 1 shifted into high.

[0024]FIG. 6 is a schematic side view of a ramp bearing positionedbetween two curved ramps of the transmission of FIG. 1.

[0025]FIG. 7 is a schematic side view of a ramp bearing positionedbetween two curved ramps of the transmission of FIG. 1.

[0026]FIG. 8 is a schematic side view of a ramp bearing positionedbetween two curved ramps of the transmission of FIG. 1.

[0027]FIG. 9 is a perspective view of the power adjuster sub-assembly ofthe transmission of FIG. 1.

[0028]FIG. 10 is a cutaway perspective view of the shifting sub-assemblyof the transmission of FIG. 1.

[0029]FIG. 11 is a perspective view of a stationary support of thetransmission of FIG. 1.

[0030]FIG. 12 is a perspective view of the screw and nut of thetransmission of FIG. 1.

[0031]FIG. 13 is a schematic perspective view of the frame support ofthe transmission of FIG. 1.

[0032]FIG. 14 is a partial cutaway perspective view of the central rampsof the transmission of FIG. 1.

[0033]FIG. 15 is a perspective view of the perimeter ramps of thetransmission of FIG. 1.

[0034]FIG. 16 is a perspective view of the linkage sub-assembly of thetransmission of FIG. 1.

[0035]FIG. 17 is a perspective view of the disengagement mechanismsub-assembly of the transmission of FIG. 1.

[0036]FIG. 18 is a perspective view of the handlegrip shifter of thetransmission of FIG. 1.

[0037]FIG. 19 is a cutaway side view of an alternative embodiment of thetransmission of FIG. 1.

[0038]FIG. 20 is a cutaway side view of yet another alternativeembodiment of the transmission of FIG. 1.

[0039]FIG. 21 is a perspective view of the transmission of FIG. 20depicting a torsional brace.

[0040]FIG. 22 is a perspective view of an alternative disengagementmechanism of the transmission of FIG. 1.

[0041]FIG. 23 is another perspective view of the alternativedisengagement mechanism of FIG. 22.

[0042]FIG. 24 is a view of a sub-assembly of an alternative embodimentof the axial force generators of the transmission of FIG. 20.

[0043]FIG. 25 is a schematic cross sectional view of the splines andgrooves of the axial force generators of FIG. 24.

[0044]FIG. 26 is a perspective view of an alternative disengagementmechanism of the transmission of FIG. 1.

[0045]FIG. 27 is a perspective view of the alternative disengagementmechanism of FIG. 26.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0046] Embodiments of the invention will now be described with referenceto the accompanying figures, wherein like numerals refer to likeelements throughout. The terminology used in the description presentedherein is not intended to be interpreted in any limited or restrictivemanner simply because it is being utilized in conjunction with adetailed description of certain specific embodiments of the invention.Furthermore, embodiments of the invention may include several novelfeatures, no single one of which is solely responsible for its desirableattributes or which is essential to practicing the inventions hereindescribed.

[0047] The transmissions described herein are of the type that utilizespeed adjuster balls with axes that tilt as described in U.S. patentapplication Ser. No. 09/695,757, filed on Oct. 24, 2000 and theinformation disclosed in that application is hereby incorporated byreference for all that it discloses. A drive (input) disk and a driven(output) disk are in contact with the speed adjuster balls. As the ballstilt on their axes, the point of rolling contact on one disk movestoward the pole or axis of the ball, where it contacts the ball at acircle of decreasing diameter, and the point of rolling contact on theother disk moves toward the equator of the ball, thus contacting thedisk at a circle of increasing diameter. If the axis of the ball istilted in the opposite direction, the disks respectively experience theconverse situation. In this manner, the ratio of rotational speed of thedrive disk to that of the driven disk, or the transmission ratio, can bechanged over a wide range by simply tilting the axes of the speedadjuster balls.

[0048] With reference to the longitudinal axis of embodiments of thetransmission, the drive disk and the driven disk can be located radiallyoutward from the speed adjuster balls, with an idler-type generallycylindrical support member located radially inward from the speedadjuster balls, so that each ball makes three-point contact with theinner support member and the outer disks. The drive disk, the drivendisk, and the support member can all rotate about the same longitudinalaxis. The drive disk and the driven disk can be shaped as simple disksor can be concave, convex, cylindrical or any other shape, depending onthe configuration of the input and output desired. The rolling contactsurfaces of the disks where they engage the speed adjuster balls canhave a flat, concave, convex or other profile, depending on the torqueand efficiency requirements of the application.

[0049] Referring to FIGS. 1 and 2, an embodiment of a continuouslyvariable transmission 100 is disclosed. The transmission 100 is shroudedin a hub shell 40, which functions as an output disk and is desirable invarious applications, including those in which a vehicle (such as abicycle or motorcycle) has the transmission contained within a drivenwheel. The hub shell 40 can; in certain embodiments, be covered by a hubcap 67. At the heart of the transmission 100 are a plurality of speedadjusters 1 that can be spherical in shape and are circumferentiallyspaced more or less equally or symmetrically around the centerline, oraxis of rotation, of the transmission 100. In the illustratedembodiment, eight speed adjusters 1 are used. However, it should benoted that more or fewer speed adjusters 1 can be used depending on theuse of the transmission 100. For example, the transmission may include3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more speed adjusters. Theprovision for more than 3, 4, or 5 speed adjusters can provide certainadvantages including, for example, widely distributing the forcesexerted on the individual speed adjusters 1 and their points of contactwith other components of the transmission 100. Certain embodiments inapplications with low torque but a high transmission ratio can use fewspeed adjusters 1 but large speed adjusters 1, while certain embodimentsin applications where high torque and a transmission high transmissionratio can use many speed adjusters 1 and large speed adjusters 1. Otherembodiments in applications with high torque and a low transmissionratio can use many speed adjusters 1 and small speed adjusters 1.Finally, certain embodiments in applications with low torque and a lowtransmission ratio may use few speed adjusters 1 and small speedadjusters 1.

[0050] Spindles 3 are inserted through holes that run through the centerof each of the speed adjusters 1 to define an axis of rotation for eachof the speed adjusters 1. The spindles 3 are generally elongated shaftsabout which the speed adjusters 1 rotate, and have two ends that extendout of either end of the hole through the speed adjusters 1. Certainembodiments will have cylindrical shaped spindles 3, though any shapecan be used. The speed adjusters 1 are mounted to freely rotate aboutthe spindles 3. In FIG. 1, the axes of rotation of the speed adjusters 1are shown in an approximately horizontal direction (i.e., parallel tothe main axis of the transmission 100).

[0051]FIGS. 1, 4 and 5, can be utilized to describe how the axes of thespeed adjusters 1 can be tilted in operation to shift the transmission100. FIG. 4 depicts the transmission 100 shifted into a low transmissionratio, or low, while FIG. 5 depicts the transmission 100 shifted into ahigh transmission ratio, or high. Now also referring to FIGS. 9 and 10,a plurality of spindle supports 2 are attached to the spindles 3 neareach of the ends of the spindles 3 that extend out of the holes boredthrough the speed adjusters 1, and extend radially inward from thosepoints of attachment toward the axis of the transmission 100. In oneembodiment, each of the spindle supports 2 has a through bore thatreceives one end of one of the spindles 3. The spindles 3 preferablyextend through and beyond the spindle supports 2 such that they have anexposed end. In the embodiments illustrated, the spindles 3advantageously have spindle rollers 4 coaxially and slidingly positionedover the exposed ends of the spindles 3. The spindle rollers 4 aregenerally cylindrical wheels fixed axially on the spindles 3 outside ofand beyond the spindle supports 2 and rotate freely about the spindles3. Referring also to FIG. 11, the spindle rollers 4 and the ends of thespindles 3 fit inside grooves 6 that are cut into a pair of stationarysupports 5 a, 5 b.

[0052] Referring to FIGS. 4, 5 and 11, the stationary supports 5 a, 5 bare generally in the form of parallel disks annularly located about theaxis of the transmission on either side of the power adjusters 1. As therotational axes of the speed adjusters 1 are changed by moving thespindle supports 2 radially out from the axis of the transmission 100 totilt the spindles 3, each spindle roller 4 fits into and follows agroove 6 cut into one of the stationary supports 5 a, 5 b. Any radialforce, not rotational but a transaxial force, the speed adjusters 1 mayapply to the spindles 3 is absorbed by the spindles 3, the spindlerollers 4 and the sides 81 of the grooves 6 in the stationary supports 5a, 5 b. The stationary supports 5 a, 5 b are mounted on a pair of splitshafts 98, 99 positioned along the axis of the transmission 100. Thesplit shafts 98, 99 are generally elongated cylinders that define asubstantial portion of the axial length of the transmission 100 and canbe used to connect the transmission 100 to the object that uses it. Eachof the split shafts 98, 99 has an inside end near the middle of thetransmission 100 and an outside end that extends out of the internalhousing of the transmission 100. The split shafts 98, 99 are preferablyhollow so as to house other optional components that may be implemented.The stationary supports 5 a, 5 b, each have a bore 82, through which thesplit shafts 98, 99 are inserted and rigidly attached to prevent anyrelative motion between the split shafts 98, 99 and the stationarysupports 5 a, 5 b. The stationary supports 5 a, 5 b are preferablyrigidly attached to the ends of the split shafts 98, 99 closest to thecenter of the transmission 100. A stationary support nut 90 may bethreaded over the split shaft 99 and tightened against the stationarysupport 5 b on corresponding threads of the stationary support 5 a, 5 b.The grooves 6 in the stationary supports 5 a, 5 b referred to above,extend from the outer circumference of the stationary supports 5 a, 5 bradially inwardly towards the split shafts 98, 99. In most embodiments,the groove sides 81 of the grooves 6 are substantially parallel to allowthe spindle rollers 4 to roll up and down the groove sides 81 as thetransmission 100 is shifted. Also, in certain embodiments, the depth ofthe grooves 6 is substantially constant at the circumference 9 of thestationary supports 5 a, 5 b, but the depth of the grooves 6 becomesshallower at points 7 closer to the split shaft 98, 99, to correspond tothe arc described by the ends of the spindles 3 as they are tilted, andto increase the strength of the stationary supports 5 a, 5 b. As thetransmission 100 is shifted to a lower or higher transmission ratio bychanging the rotational axes of the speed adjusters 1, each one of thepairs of spindle rollers 4, located on the opposite ends of a singlespindle 3, move in opposite directions along their corresponding grooves6.

[0053] Referring to FIGS. 9 and 11, stationary support wheels 30 can beattached to the spindle supports 2 with stationary support wheel pins 31or by any other attachment method. The stationary support wheels 30 arecoaxially and slidingly mounted over the stationary support wheel pins31 and secured with standard fasteners, such as ring clips for example.In certain embodiments, one stationary support wheel 30 is positioned oneach side of a spindle 2 with enough clearance to allow the stationarysupport wheels 30 to roll radially on concave surfaces 84 of thestationary supports 5 a, 5 b when the transmission 100 is shifted. Incertain embodiments, the concave surfaces 84 are concentric with thecenter of the speed adjusters 1.

[0054] Referring to FIGS. 2, 3, and 11, a plurality of elongated spacers8 are distributed radially about, and extend generally coaxially with,the axis of the transmission. The elongated spacers 8 connect thestationary supports 5 a to one another to increase the strength andrigidity of the internal structure of the transmission 100. The spacers8 are oriented generally parallel to one another, and in someembodiments, each one extends from a point at one stationary support 5 anear the outer circumference to a corresponding point on the otherstationary support 5 b. The spacers 8 can also precisely fix thedistance between the stationary supports 5 a, 5 b, align the grooves 6of the stationary supports 5 a, 5 b, ensure that the stationary supports5 a, 5 b are parallel, and form a connection between the split shafts98, 99. In one embodiment, the spacers 8 are pressed through spacerholes 46 in the stationary supports 5 a, 5 b. Although eight spacers 8are illustrated, more or less spacers 8 can be used. In certainembodiments, the spacers 8 are located between two speed adjusters 1.

[0055] Referring to FIGS. 1, 3, and 13, the stationary support 5 a, incertain embodiments, is rigidly attached to a stationary support sleeve42 located coaxially around the split shaft 98, or alternately, isotherwise rigidly attached to or made an integral part of the splitshaft 98. The stationary sleeve 42 extends through the wall of the hubshell 40 and attaches to a frame support 15. In some embodiments, theframe support 15 fits coaxially over the stationary sleeve 42 and isrigidly attached to the stationary sleeve 42. The frame support 15 usesa torque lever 43, in some embodiments, to maintain the stationaryposition of the stationary sleeve 42. The torque lever 43 providesrotational stability to the transmission 100 by physically connectingthe stationary sleeve 42, via the frame support 15, and therefore therest of the stationary parts to a fixed support member of the item towhich the transmission 100 is to be mounted. A torque nut 44 threadsonto the outside of the stationary sleeve 42 to hold the torque lever 43in a position that engages the frame support 15. In certain embodiments,the frame support 15 is not cylindrical so as to engage the torque lever43 in a positive manner thereby preventing rotation of the stationarysleeve 42.

[0056] For example, the frame support 15 could be a square of thicknessequal to the torque lever 43 with sides larger than the stationarysleeve and with a hole cut out of its center so that the square may fitover the stationary sleeve 42, to which it may then be rigidly attached.Additionally, the torque lever 43 could be a lever arm of thicknessequal to that of the frame support 15 with a first end near the framesupport 15 and a second end opposite the first. The torque lever 43, insome embodiments, also has a bore through one of its ends, but this boreis a square and is a slightly larger square than the frame support 15 sothe torque lever 43 could slide over the frame support 15 resulting in arotational engagement of the frame support 15 and the torque lever 43.Furthermore, the lever arm of the torque lever 43 is oriented so thatthe second end extends to attach to the frame of the bike, automobile,tractor or other application that the transmission 100 is used upon,thereby countering any torque applied by the transmission 100 throughthe frame support 15 and the stationary sleeve 42. A stationary supportbearing 48 fits coaxially around the stationary sleeve 42 and axiallybetween the outside edge of the hub shell 40 and the torque lever 43.The stationary support bearing 48 supports the hub shell 40, permittingthe hub shell 40 to rotate relative to the stationary support sleeve 42.

[0057] Referring to FIGS. 1 and 10, in some embodiments, shifting ismanually activated by rotating a rod 10, positioned in the hollow splitshaft 98. A worm screw 11, a set of male threads in some embodiments, isattached to the end of the rod 10 that is in the center of thetransmission 100, while the other end of the rod 10 extends axially tothe outside of the transmission 100 and has male threads affixed to itsouter surface. In one embodiment, the worm screw 11 is threaded into acoaxial sleeve 19 with mating threads, so that upon rotation of the rod10 and worm screw 11, the sleeve 19 moves axially. The sleeve 19 isgenerally in the shape of a hollow cylinder that fits coaxially aroundthe worm screw 11 and rod 10 and has two ends, one near stationarysupport 5 a and one near stationary support 5 b. The sleeve 19 isaffixed at each end to a platform 13, 14. The two platforms 13, 14 areeach generally of the form of an annular ring with an inside diameter,which is large enough to fit over and attach to the sleeve 19, and isshaped so as to have two sides. The first side is a generally straightsurface that dynamically contacts and axially supports the supportmember 18 via two sets of contact bearings 17 a, 17 b. The second sideof each platform 13, 14 is in the form of a convex surface. Theplatforms 13, 14 are each attached to one end of the outside of thesleeve 19 so as to form an annular trough around the circumference ofthe sleeve 19. One platform 13 is attached to the side neareststationary support 5 a and the other platform 14 is attached to the endnearest stationary support 5 b. The convex surface of the platforms 13,14 act as cams, each contacting and pushing multiple shifting wheels 21.To perform this camming function, the platforms 13, 14 preferablytransition into convex curved surfaces 97 near their perimeters(farthest from the split shafts 98, 99), that may or may not be radii.This curve 97 contacts with the shifting wheels 21 so that as theplatforms 13, 14 move axially, a shifting wheel 21 rides along theplatform 13, 14 surface in a generally radial direction forcing thespindle support 2 radially out from, or in toward, the split shaft 98,99, thereby changing the angle of the spindle 3 and the rotation axis ofthe associated speed adjuster 1. In certain embodiments, the shiftingwheels 21 fit into slots in the spindle supports 2 at the end nearestthe centerline of the transmission 100 and are held in place by wheelaxles 22.

[0058] Still referring to FIGS. 1 and 10, a support member 18 is locatedin the trough formed between the platforms 13, 14 and sleeve 19, andthus moves in unison with the platforms 13, 14 and sleeve 19. In certainembodiments, the support member 18 is generally of one outside diameterand is generally cylindrical along the center of its inside diameterwith a bearing race on each edge of its inside diameter. In otherembodiments, the outer diameter of the support member 18 can benon-uniform and can be any shape, such as ramped or curved. The supportmember 18 has two sides, one near one of the stationary supports 5 a andone near the other stationary support 5 b. The support member 18 rideson two contact bearings 17 a, 17 b to provide rolling contact betweenthe support member 18 and the sleeve 19. The contact bearings 17 a, 17 bare located coaxially around the sleeve 19 where the sleeve 19intersects the platforms 13, 14 allowing the support member 18 to freelyrotate about the axis of the transmission 100. The sleeve 19 issupported axially by the worm screw 11 and the rod 10 and therefore,through this configuration, the sleeve 19 is able to slide axially asthe worm screw 11 positions it. When the transmission 100 is shifted,the sleeve 19 moves axially, and the bearings 17 a, 17 b, support member18, and platforms 13, 14, which are all attached either dynamically orstatically to the sleeve, move axially in a corresponding manner.

[0059] In certain embodiments, the rod 10 is attached at its endopposite the worm screw 11 to a shifting tube 50 by a rod nut 51, and arod flange 52. The shifting tube 50 is generally in the shape of a tubewith one end open and one end substantially closed. The open end ofshifting tube 50 is of a diameter appropriate to fit over the end of thesplit shaft 98 that extends axially out of the center of thetransmission 100. The substantially closed end of the shifting tube 50has a small bore through it so that the end of the rod 10 that isopposite of the worm screw 11 can pass through it as the shifting tube50 is placed over the outside of the split shaft 98. The substantiallyclosed end of the shifting tube 50 can then be fixed in axial place bythe rod nut 51, which is fastened outside of the shifting tube 50, andthe rod flange 52, which in turn is fastened inside of the shiftingtube's 50 substantially closed end, respectively. The shifting tube 50can, in some embodiments, be rotated by a cable 53 attached to theoutside of the shifting tube 50. The cable 53, in these embodiments, isattached to the shifting tube 50 with a cable clamp 54 and cable screw56, and then wrapped around the shifting tube 50 so that when tension isapplied to the cable 53 a moment is developed about the center of theaxis of the shifting tube 50 causing it to rotate. The rotation ofshifting tube 50 may alternately be caused by any other mechanism suchas a rod, by hand rotation, a servo-motor or other method contemplatedto rotate the rod 10. In certain embodiments, when the cable 53 ispulled so that the shifting tube 50 rotates clockwise on the split shaft98, the worm screw 11 rotates clockwise, pulling the sleeve 19, supportmember 18 and platforms 13, 14, axially toward the shifting tube 50 andshifting the transmission 100 towards a low transmission ratio. A wormspring 55, as illustrated in FIG. 3, that can be a conical coiled springcapable of producing compressive and torsional force, attached at theend of the worm screw 11, is positioned between the stationary support 5b and the platform 14 and resists the shifting of the transmission 100.The worm spring 55 is designed to bias the shifting tube 50 to rotate soas to shift the transmission 100 towards a low transmission ratio insome embodiments and towards a high transmission ratio in otherembodiments.

[0060] Referring to FIGS. 1, 10, and 11, axial movement of the platforms13, 14, define the shifting range of the transmission 100. Axialmovement is limited by inside faces 85 on the stationary supports 5 a, 5b, which the platforms 13, 14 contact. At an extreme high transmissionratio, platform 14 contacts the inside face 85 on one of the stationarysupports 5 a, 5 b, and at an extreme low transmission ratio, theplatform 13 contacts the inside face 85 on the other one of thestationary supports 5 a, 5 b. In many embodiments, the curvature of theconvex radii of the platforms 13, 14, are functionally dependant on thedistance from the center of a speed adjuster 1 to the center of thewheel 21, the radius of the wheel 21, the distance between the twowheels 21 that are operably attached to each speed adjuster 1, and theangle of tilt of the speed adjuster 1 axis.

[0061] Although a left hand threaded worm screw 11 is disclosed, a righthand threaded worm screw 11, the corresponding right hand wrappedshifting tube 50, and any other combination of components just describedthat is can be used to support lateral movement of the support member 18and platforms 13, 14, can be used. Additionally, the shifting tube 50can have internal threads that engage with external threads on theoutside of the split shaft 98. By adding this threaded engagement, theshifting tube 50 will move axially as it rotates about the split shaft98 causing the rod 10 to move axially as well. This can be employed toenhance the axial movement of the sleeve 19 by the worm screw 11 so asto magnify the effects of rotating the worm screw 11 to more rapidlyshift the gear ratio or alternatively, to diminish the effects ofrotating the worm screw 11 so as to slow the shifting process andproduce more accurate adjustments of the transmission 100.

[0062] Referring to FIGS. 10 and 18, manual shifting may be accomplishedby use of a rotating handlegrip 132, which can be coaxially positionedover a stationary tube, a handlebar 130, or some other structuralmember. In certain embodiments, an end of the cable 53 is attached to acable stop 133, which is affixed to the rotating handlegrip 132. In someembodiments, internal forces of the transmission 100 and the conicalspring 55 tend to bias the shifting of the transmission towards a lowertransmission ratio. As the rotating handlegrip 132 is rotated by theuser, the cable 53, which can be wrapped along a groove around therotating handlegrip 132, winds or unwinds depending upon the directionof rotation of the cable 53, simultaneously rotating the shifting tube50 and shifting the transmission 100 towards a higher transmissionratio. A set of ratchet teeth 134 can be circumferentially positioned onone of the two sides of the rotating handlegrip 132 to engage a matingset of ratchet teeth on a first side of a ratcheted tube 135, therebypreventing the rotating handlegrip 132 from rotating in the oppositedirection. A tube clamp 136, which can bean adjustable screw allowingfor variable clamping force, secures the ratcheted tube 135 to thehandlebar 130. When shifting in the opposite direction, the rotatinghandlegrip 132, is forcibly rotated in the opposite direction toward alower transmission ratio, causing the tube clamp 136 to rotate in unisonwith the rotating handlegrip 132. A handlebar tube 137, positionedproximate to the ratcheted tube 135, on a side opposite the ratchetteeth 134, is rigidly clamped to the handlebar 130 with a tube clamp138, thereby preventing disengagement of the ratcheted tube 135 from theratchet teeth 134. A non-rotating handlegrip 131 is secured to thehandlebar 130 and positioned proximate to the rotating handlegrip 132,preventing axial movement of the rotating handlegrip 132 and preventingthe ratchet teeth 134 from becoming disengaged from the ratcheted tube135.

[0063] Now referring to embodiments illustrated by FIGS. 1, 9, and 11, aone or more stationary support rollers 30 can be attached to eachspindle support 2 with a roller pin 31 that is inserted through a holein each spindle support 2. The roller pins 31 are of the proper size anddesign to allow the stationary support rollers 30 to rotate freely overeach roller pin 31. The stationary support rollers 30 roll along concavecurved surfaces 84 on the sides of the stationary supports 5 a, 5 b thatface the speed adjusters 1. The stationary support rollers 30 provideaxial support to prevent the spindle supports 2 from moving axially andalso to ensure that the spindles 2 tilt easily when the transmission 100is shifted.

[0064] Referring to FIGS. 1, 12, 14, and 17, a three spoked drive disk34, located adjacent to the stationary support 5 b, partiallyencapsulates but generally does not contact the stationary support 5 b.The drive disk 34 may have two or more spokes or may be a solid disk.The spokes reduce weight and aid in assembly of the transmission 100 ineembodiments using them, however a solid disk can be used. The drive disk34 has two sides, a first side that contacts with the speed adjusters 1,and a second side that faces opposite of the first side. The drive disk34 is generally an annular disk that fits coaxially over, and extendsradially from, a set of female threads or nut 37 at its inner diameter.The outside diameter of the drive disk 34 is designed to fit within thehub shell 40, if the hub shell 40 employed is the type that encapsulatesthe speed adjusters 1 and the drive disk 34, and engages with the hubcap 67. The drive disk 34 is rotatably coupled to the speed adjusters 1along a circumferential bearing surface on the lip of the first side ofthe drive disk 34. As mentioned above, some embodiments of the drivedisk 34 have a set of female threads 37, or a nut 37, at its center, andthe nut 37 is threaded over a screw 35, thereby engaging the drive disk34 with the screw 35. The screw 35 is rigidly attached to a set ofcentral screw ramps 90 that are generally a set of raised surfaces on anannular disk that is positioned coaxially over the split shaft 99. Thecentral screw ramps 90 are driven by a set of central drive shaft ramps91, which are similarly formed on a generally annular disk. The rampsurfaces of the central drive ramps 91 and the central screw ramps 90can be linear, but can be any other shape, and are in operable contactwith each other. The central drive shaft ramps 91, coaxially and rigidlyattached to the drive shaft 69, impart torque and an axial force to thecentral screw ramps 90 that can then be transferred to the drive disk34. A central drive tension member 92, positioned between the centraldrive shaft ramps 91 and the central screw ramps 90, produces torsionaland/or compressive force, ensuring that the central ramps 90, 91 are incontact with one another.

[0065] Still referring to FIGS. 1, 12, 14, and 17, the screw 35, whichis capable of axial movement, can be biased to move axially away fromthe speed adjusters 1 with an annular thrust bearing 73 that contacts arace on the side of the screw 35 that faces the speed adjusters 1. Anannular thrust washer 72, coaxially positioned over the split shaft 99,contacts the thrust bearing 73 and can be pushed by a pin 12 thatextends through a slot in the split shaft 99. A compression member 95capable of producing a compressive force is positioned in the bore ofthe hollow split shaft 99 at a first end. The compression member 95,which may be a spring, contacts the pin 12 on one end, and at a secondend contacts the rod 10. As the rod 10 is shifted towards a highertransmission ratio and moves axially, it contacts the compression member95, pushing it against the pin 12. Internal forces in the transmission100 will bias the support member 18 to move towards a high transmissionratio position once the transmission ratio goes beyond a 1:1transmission ratio towards high and the drive disk 34 rotates moreslowly than the hub shell 40. This bias pushes the screw 35 axially sothat it either disconnects from the nut 37 and no longer applies anaxial force or a torque to the drive disk 34, or reduces the force thatthe screw 35 applies to the nut 37. In this situation, the percentage ofaxial force applied to the drive disk 34 by the perimeter ramps 61increases. It should be noted that the internal forces of thetransmission 100 will also bias the support member 18 towards low oncethe support member 18 passes beyond a position for a 1:1 transmissionratio towards low and the hub shell 40 rotates more slowly than thedrive disk 34. This beneficial bias assists shifting as rpm's drop andtorque increases when shifting into low.

[0066] Still referring to FIGS. 1, 12, 14, and 17, the drive shaft 69,which is a generally tubular sleeve having two ends and positionedcoaxial to the outside of the split shaft 99, has at one end theaforementioned central drive shaft ramps 91 attached to it, while theopposite end faces away from the drive disk 34. In certain embodiments,a bearing disk 60 is attached to and driven by the drive shaft 69. Thebearing disk 60 can be splined to the drive shaft 69, providing forlimited axial movement of the bearing disk 60, or the bearing disk 60can be rigidly attached to the drive shaft 69. The bearing disk 60 isgenerally a radial disk coaxially mounted over the drive shaft 69extending radially outward to a radius generally equal to that of thedrive disk 34. The bearing disk 60 is mounted on the drive shaft 69 in aposition near the drive disk 34, but far enough away to allow space fora set of perimeter ramps 61, associated ramp bearings 62, and a bearingrace 64, all of which are located between the drive disk 34 and thebearing disk 67. In certain embodiments, the plurality of perimeterramps 61 can be concave and are rigidly attached to the bearing disk 60on the side facing the drive disk 34. Alternatively, the perimeter ramps61 can be convex or linear, depending on the use of the transmission100. Alternatively, the bearing race 64, can be replaced by a second setof perimeter ramps 97, which may also be linear, convex, or concave, andwhich are rigidly attached to the drive disk 34 on the side facing thebearing disk 60. The ramp bearings 62 are generally a plurality ofbearings matching in number the perimeter ramps 61. Each one of theplurality of ramp bearings 62 is located between one perimeter ramp 61and the bearing race 64, and is held in its place by a compressive forceexerted by the ramps 61 and also by a bearing cage 63. The bearing cage63 is an annular ring coaxial to the split shaft 99 and located axiallybetween the concave ramps 61 and convex ramps 64. The bearing cage 63has a relatively large inner diameter so that the radial thickness ofthe bearing cage 63 is only slightly larger than the diameter of theramp bearings 62 to house the ramp bearings 62. Each of the rampbearings 62 fits into a hole that is formed in the radial thickness ofthe bearing cage 63 and these holes, together with the previouslymentioned compressive force, hold the ramp bearings 62 in place. Thebearing cage 63, can be guided into position by a flange on the drivedisk 34 or the bearing disk 60, which is slightly smaller than theinside diameter of the bearing cage 63.

[0067] Referring to FIGS. 1, 6, 7, 8, and 15, the bearing disk 60, theperimeter ramps 61, and a ramp bearing 62 of one embodiment aredepicted. Referring specifically to FIG. 6, a schematic view shows aramp bearing 62 contacting a concave perimeter ramp 61, and a secondconvex perimeter ramp 97. Referring specifically to FIG. 7, a schematicview shows the ramp bearing 62, the concave perimeter ramp 61, and thesecond convex perimeter ramp 97 of FIG. 6 at a different torque ortransmission ratio. The position of the ramp bearings 62 on theperimeter ramps 61 depicted in FIG. 7 produces less axial force than theposition of the ramp bearings 62 on the perimeter ramps 61 depicted inFIG. 6. Referring specifically to FIG. 8, a ramp bearing 62 is showncontacting a convex perimeter ramp 61, and a concave second perimeterramp 97 in substantially central positions on those respective ramps. Itshould be noted that changes in the curves of the perimeter ramps 61, 97change the magnitude of the axial force applied to the power adjusters 1at various transmission ratios, thereby maximizing efficiency indifferent gear ratios and changes in torque. Depending on the use forthe transmission 100, many combinations of curved or linear perimeterramps 61, 97 can be used. To simplify operation and reduce cost, in someapplications one set of perimeter ramps may be eliminated, such as thesecond set of perimeter tramps 97, which are then replaced by a bearingrace 64. To further reduce cost, the set of perimeter ramps 61 may havea linear inclination.

[0068] Referring to FIG. 1, a coiled spring 65 having two ends wrapscoaxially around the drive shaft 69 and is attached at one end to thebearing disk 60 and at its other end to the drive disk 34. The coiledspring 65 provides force to keep the drive disk 34 in contact with thespeed adjusters 1 and biases the ramp bearings 62 up the perimeter ramps61. The coiled spring 65 is designed to minimize the axial space withinwhich it needs to operate and, in certain embodiments, the cross sectionof the coiled spring 65 is a rectangle with the radial length greaterthan the axial length.

[0069] Referring to FIG. 1, the bearing disk 60 preferably contacts anouter hub cap bearing 66 on the bearing disk 60 side that faces oppositethe concave ramps 61. The outer hub cap bearing 66 can be an annular setof roller bearings located radially outside of, but coaxial with, thecenterline of the transmission 100. The outer hub cap bearing 66 islocated radially at a position where it may contact both the hub cap 67and the bearing disk 60 to allow their relative motion with respect toone another. The hub cap 67 is generally in the shape of a disk with ahole in the center to fit over the drive shaft 69 and with an outerdiameter such that it will fit within the hub shell 40. The innerdiameter of the hub cap engages with an inner hub cap bearing 96 that ispositioned between the hub cap 67 and the drive shaft 69 and maintainsthe radial and axial alignment of the hub cap 67 and the drive shaft 69with respect to one another. The edge of the hub cap 67 at its outerdiameter can be threaded so that the hub cap 67 can be threaded into thehub shell 40 to encapsulate much of the transmission 100. A sprocket orpulley 38 or other drive train adapter, such as gearing for example, canbe rigidly attached to the rotating drive shaft 69 to provide the inputrotation. The drive shaft 69 is maintained in its coaxial position aboutthe split shaft 99 by a cone bearing 70. The cone bearing 70 is anannular bearing mounted coaxially around the split shaft 99 and allowsrolling contact between the drive shaft 69 and the split shaft 99. Thecone bearing 70 may be secured in its axial place by a cone nut 71 whichthreads onto the split shaft 99 or by any other fastening method.

[0070] In operation of certain embodiments, an input rotation from thesprocket or pulley 38 is transmitted to the drive shaft 69, which inturn rotates the bearing disk 60 and the plurality of perimeter ramps 61causing the ramp bearings 62 to roll up the perimeter ramps 61 and pressthe drive disk 34 against the speed adjusters 1. The ramp bearings 62also transmit rotational energy to the drive disk 34 as they are wedgedin between, and therefore transmit rotational energy between, theperimeter ramps 61 and the convex ramps 64. The rotational energy istransferred from the drive disk 34 to the speed adjusters 1, which inturn rotate the hub shell 40 providing the transmission 100 outputrotation and torque.

[0071] Referring to FIG. 16, a latch 115 rigidly attaches to the side ofthe drive disk 34 that faces the bearing disk 60 and engages a hook 114that is rigidly attached to a first of two ends of a hook lever 113. Theengaging area under the latch 115 opening is larger than the width ofthe hook 114 and provides extra room for the hook 114 to move radially,with respect to the axis, within the confines of the latch 114 when thedrive disk 34 and the bearing disk 60 move relative to each other. Thehook lever 113 is generally a longitudinal support member for the hook114 and at its second end, the hook lever 113 has an integral hook hinge116 that engages with a middle hinge 119 via a first hinge pin 111. Themiddle hinge 119 is integral with a first end of a drive disk lever 112,a generally elongated support member having two ends. On its second end,the drive disk lever 112 has an integral drive disk hinge 117, whichengages a hinge brace 110 via the use of a second hinge pin 118. Thehinge brace 110 is generally a base to support the hook 114, the hooklever 113, the hook hinge 116, the first hinge pin 111, the middle hinge119, the drive disk lever 112 the second hinge pin 118, and the drivedisk hinge 117, and it is rigidly attached to the bearing disk 60 on theside facing the drive disk 34. When the latch 73 and hook 72 are engagedthe ramp bearings 62 are prevented from rolling to an area on theperimeter ramps 61 that does not provide the correct amount of axialforce to the drive disk 34. This ensures that all rotational forceapplied to the ramp bearings 62 by perimeter ramps 61 is transmitted tothe drive disk 34.

[0072] Referring to FIGS. 1 and 17, a disengagement mechanism for oneembodiment of the transmission 100 is described to disengage the drivedisk 34 from the speed adjusters 1 in order to coast. On occasions thatinput rotation to the transmission 100 ceases, the sprocket or pulley 38stops rotating but the hub shell 40 and the speed adjusters 1 cancontinue to rotate. This causes the drive disk 34 to rotate so that theset of female threads 37 in the bore of the drive disk 34 wind onto themale threaded screw 35, thereby moving the drive disk 34 axially awayfrom the speed adjusters 1 until the drive disk 34 no longer contactsthe speed adjusters 1. A toothed rack 126, rigidly attached to the drivedisk 34 on the side facing the bearing disk 60, has teeth that engageand rotate a toothed wheel 124 as the drive disk 34 winds onto the screw35 and disengages from the power adjusters 1. The toothed wheel 124, hasa bore in its center, through which a toothed wheel bushing 121 islocated, providing for rotation of the toothed wheel 124. Clips 125 thatare coaxially attached over the toothed wheel bushing 121 secure thetoothed wheel 124 in position, although any means of fastening may beused. A preloader 120, coaxially positioned over and clamped to thecentral drive shaft ramps 91, extends in a direction that is radiallyoutward from the center of the transmission 100. The preloader 120, of aresilient material capable of returning to its original shape whenflexed, has a first end 128 and a second end 127. The first end of thepreloader 128 extends through the toothed wheel bushing 121 andterminates in the bearing cage 63. The first end of the preloader 128biases the bearing cage 63 and ramp bearings 62 up the ramps 61,ensuring contact between the ramp bearings 62 and the ramps 61, and alsobiases the toothed wheel 124 against the toothed rack 126. A pawl 123,engages the toothed wheel 124, and in one embodiment engages the toothedwheel 124 on a side substantially opposite the toothed rack 126. Thepawl 123 has a bore through which a pawl bushing 122 passes, allowingfor rotation of the pawl 123. Clips 125, or other fastening means securethe pawl 123 to the pawl bushing 121. A pawl spring 122 biases rotationof the pawl 123 to engage the toothed wheel 124, thereby preventing thetoothed wheel 124 from reversing its direction of rotation when thedrive disk 34 winds onto the screw 35. The pawl bushing 121 ispositioned over a second end of the preloader 127, which rotates inunison with the drive shaft 69.

[0073] Referring again to FIG. 1, a coiled spring 65, coaxial with andlocated around the drive shaft 69, is located axially between andattached by pins or other fasteners (not shown) to both the bearing disk60 at one end and drive disk 34 at the other end. In certainembodiments, the coiled spring 65 replaces the coiled spring of theprior art so as to provide more force and take less axial space in orderto decrease the overall size of the transmission 100. In someembodiments, the coiled spring 65 is produced from spring steel wirewith a rectangular profile that has a radial length or height greaterthan its axial length or width. During operation of the transmission100, the coiled spring 65 ensures contact between the speed adjusters 1and the drive disk 34. However, once the drive disk 34 has disengagedfrom the speed adjusters 1, the coiled spring 65 is prevented fromwinding the drive disk 34 so that it again contacts the speed adjusters1 by the engagement of the toothed wheel 124 and the pawl 123. When theinput sprocket, gear, or pulley 38, resumes its rotation, the pawl 123also rotates, allowing the toothed wheel 124 to rotate, thus allowingthe drive disk 34 to rotate and unwind from the screw 35 due to thetorsional force created by the coiled spring 65. Relative movementbetween the pawl 123 and the toothed wheel 124 is provided by the factthat the first end of the preloader 128 rotates at approximately halfthe speed as the second end of the preloader 127 because the first endof the preloader 128 is attached to the bearing cage 63. Also, becausethe ramp bearings 62 are rolling on the perimeter ramps 61 of thebearing disk 60, the bearing cage 63 will rotate at half the speed asthe bearing disk 60.

[0074] Referring now to FIG. 19, an alternative embodiment of thetransmission 100 of FIG. 1 is disclosed. In this embodiment, an outputdisk 201 replaces the hub shell 40 of the transmission 100 illustratedin FIG. 1. Similar to the drive disk 34, the output disk 201 contacts,and is rotated by, the speed adjusters 1. The output disk 201 issupported by an output disk bearing 202 that contacts both the outputdisk 201 and a stationary case cap 204. The case cap 204 is rigidlyattached to a stationary case 203 with case bolts 205 or any otherfasteners. The stationary case 203 can be attached to a non-movingobject such as a frame or to the machine for which its use is employed.A gear, sprocket, or pulley 206 is attached coaxially over and rigidlyto the output disk 201 outside of the case cap 204 and stationary case203. Any other type of output means can be used however, such as gearsfor example. A torsional brace 207 can be added that rigidly connectsthe split shaft 98 to the case cap 204 for additional support.

[0075] Referring now to FIGS. 20 and 21, an alternative embodiment ofthe transmission 100 of FIG. 1 is disclosed. A stationary support race302 is added on a side of stationary support 5 a facing away from thespeed adjusters 1 and engages with a stationary support bearing 301 anda rotating hub shell race 303 to maintain correct alignment of thestationary support 5 a with respect to the rotating hub shell 40. Atorsional brace 304 is rigidly attached to the stationary support 5 aand can then be rigidly attached to a stationary external component toprevent the stationary supports 5 a, 5 b from rotating during operationof the transmission 300. A drive shaft bearing 306 is positioned at anend of the drive shaft 69 facing the speed adjusters 1 and engages adrive shaft race 307 formed in the same end of the drive shaft 69 and asplit shaft race 305 formed on a radially raised portion of the splitshaft 99 to provide additional support to the drive shaft 69 and toproperly position the drive shaft 69 relative to the stationary supports5 a, 5 b.

[0076] Referring now to FIGS. 22 and 23, an alternative disengagementmechanism 400 of the transmission 100 of FIG. 1 is disclosed. A toothedwheel 402 is coaxially positioned over a wheel bushing 408 and securedin position with a clip 413 or other fastener such that it is capable ofrotation. The wheel bushing 408 is coaxially positioned over the firstend of a preloader 405 having first and second ends (both not separatelyidentified in FIGS. 22, and 23). The preloader 405 clamps resilientlyaround the central drive shaft ramps 91. The first end of the preloader405 extends into the bearing cage 63, biasing the bearing cage 63 up theperimeter ramps 61. Also positioned over the wheel bushing 408 is alever 401 that rotates around the wheel bushing 408 and that supports atoothed wheel pawl 411 and a pinion pawl 409. The toothed wheel pawl 411engages the toothed wheel 402 to control its rotation, and is positionedover a toothed wheel bushing 414 that is pressed into a bore in thelever 401. A toothed wheel pawl spring 412 biases the toothed wheel pawl411 against the toothed wheel 402. The pinion pawl 409, positionedsubstantially opposite the toothed wheel pawl 411 on the lever 401, iscoaxially positioned over a pinion pawl bushing 415 that fits intoanother bore in the lever 401 and provides for rotational movement ofthe pinion pawl 409. A pinion pawl spring 410 biases the pinion pawl 409against a pinion 403.

[0077] Referring now to FIGS. 1, 22 and 23, the pinion 403 has a bore atits center and is coaxially positioned over a first of two ends of a rodlever 404. The rod lever is an elongated lever that engages the pinionpawl 409 during coasting until input rotation of the sprocket, pulley,or gear 38 resumes. A bearing disk pin 406 that is affixed to thebearing disk 60 contacts a second end of the rod lever 404, uponrotation of the bearing disk 60, thereby pushing the rod lever 404against a drive disk pin 407, which is rigidly attached to the drivedisk 34. This action forces the first end of the rod lever 404 to swingaway from the toothed wheel 402, temporarily disconnecting the pinion403 from the toothed wheel 402, allowing the toothed wheel 402 torotate. A lever hook 401 is attached to the the lever 401 and contacts alatch (not shown) on the drive disk 34 and is thereby pushed back as thecoiled spring 65 biases the drive disk 34 to unwind and contact thespeed adjusters 1. During occasions that the input rotation of thesprocket, pulley, or gear 38 ceases, and the speed adjusters 1 continueto rotate, the drive disk 34 winds onto the screw 35 and disengages fromthe speed adjusters 1. As the drive disk 34 rotates, the drive disk pin407 disengages from the rod lever 404, which then swings the pinion 403into contact with the toothed wheel 402, preventing the drive disk 34from re-engaging the speed adjusters 1.

[0078] Referring to FIGS. 24 and 25, a sub-assembly of an alternativeset of axial force generators 500 of the transmission 300 of FIG. 20 isdisclosed. When rotated by the input sprocket, gear, or pulley 38, asplined drive shaft 501 rotates the bearing disk 60, which may havegrooves 505 in its bore to accept and engage the splines 506 of thesplined drive shaft 501. The central drive shaft ramps 508 are rigidlyattached to the bearing disk 60 or the splined drive shaft 501 androtate the central screw ramps 507, both of which have bores that clearthe splines 506 of the splined drive shaft 501. The central tensionmember 92 (illustrated in FIG. 1) is positioned between the centraldrive shaft ramps 508 and the central screw ramps 507. A grooved screw502 having a grooved end and a bearing end is rotated by the centralscrew ramps 90 and has grooves 505 on its bearing end that are widerthan the splines 506 on the splined drive shaft 501 to provide a gapbetween the splines 506 and the grooves 505. This gap between thesplines 506 and the grooves 505 allows for relative movement between thegrooved screw 502 and/or bearing disk 60 and the splined drive shaft501. On occasions when the grooved screw 502 is not rotated by thecentral drive shaft ramps 508 and the central screw ramps 507, thesplines 506 of the splined drive shaft 501 contact and rotate thegrooves 505 on the grooved screw 502, thus rotating the grooved screw502. An annular screw bearing 503 contacts a race on the bearing end ofthe grooved screw 502 and is positioned to support the grooved screw 502and the splined drive shaft 501 relative to the axis of the split shaft99. The bore of the grooved screw 502 is slightly larger than theoutside diameter of the splined drive shaft 501 to allow axial androtational relative movement of the grooved screw 502. A screw cone race504 contacts and engages the annular screw bearing 503 and has a holeperpendicular to its axis to allow insertion of a pin 12. The pin 12engages the rod 10, which can push on the pin 12 and move the groovedscrew 502 axially, causing it to disengage from, or reduce the axialforce that it applies to, the nut 37.

[0079] Referring to FIG. 26, an alternative disengagement means 600 ofthe disengagement means 400 of FIGS. 22 and 23 is disclosed. The lever401 is modified to eliminate the T-shape used to mount both the pinionpawl 409 and the toothed wheel pawl 411 so that the new lever 601 hasonly the toothed wheel pawl 411 attached to it. A second lever 602,having a first end and a second end. The pinion pawl 409 is operablyattached to the first end of the second lever 602. The second lever 602has a first bore through which the first end of the preloader 405 isinserted. The second lever 602 is rotatably mounted over the first endof the preloader 405. The second lever 602 has a second bore in itssecond end through which the second end of the preloader 603 isinserted. When rotation of the sprocket, gear, or pulley 38 ceases, thedrive disk 34 continues to rotate forward and wind onto the screw 36until it disengages from the speed adjusters 1. The first end of thepreloader 405 rotates forward causing the pinion pawl 409 to contact androtate the pinion 403 clockwise. This causes the toothed wheel 402 torotate counter-clockwise so that the toothed wheel pawl 411 passes overone or more teeth of the toothed wheel 402, securing the drive disk 34and preventing it from unwinding off of the screw 36 and contacting thespeed adjusters 1. When rotation of the sprocket, gear, or pulley 38resumes, the second end of the preloader 603 rotates, contacting thesecond end of the second lever 602 causing the pinion pawl 409 to swingout and disengage from the pinion 403, thereby allowing the drive disk34 to unwind and reengage with the speed adjusters 1.

[0080] With this description in place, some of the particularimprovements and advantages of the present invention will now bedescribed. Note that not all of these improvements are necessarily foundin all embodiments of the invention.

[0081] Referring to FIG. 1, a current improvement in some embodimentsincludes providing variable axial force to the drive disk 34 to respondto differing loads or uses. This can be accomplished by the use ofmultiple axial force generators. Axial force production can switchbetween a screw 35 and a nut 37, with associated central drive shaftramps 91 and screw ramps 90, to perimeter ramps 61, 64. Or the screw 35,central ramps 90, 91, and perimeter ramps 61, 64 can share axial forceproduction. Furthermore, axial force at the perimeter ramps 61, 64 canbe variable. This can be accomplished by the use of ramps of variableinclination and declination, including concave and convex ramps.Referring to FIG. 1 and FIGS. 6-8 and the previous detailed description,an embodiment is disclosed where affixed to the bearing disk 60 is afirst set of perimeter ramps 61, which may be concave, with which theramp bearings 62 contact. Opposite the first set of perimeter ramps 61are a second set of perimeter ramps 97 that are attached to the drivedisk 34, which may be convex, and which are in contact with the rampbearings 62. The use of concave and convex ramps to contact the rampbearings 62 allows for non-linear increase or decrease in the axial loadupon the drive disk 34 in response to adjustments in the position of thespeed adjusters 1 and the support member 18.

[0082] Another improvement of certain embodiments includes positivelyengaging the bearing disk 60 and the drive disk 34 to provide greaterrotational transmission and constant axial thrust at certain levels oftorque transmission. Referring to an embodiment illustrated in FIG. 1 asdescribed above, this may be accomplished, for example, by the use ofthe hook 114 and latch 115 combination where the hook 114 is attached tothe bearing cage 63 that houses the ramp bearings 62 between the drivedisk 34 and the bearing disk 60, and the latch 115 is attached to thedrive disk 34 that engages with the hook 114 when the ramp bearings 62reach their respective limit positions on the ramp faces. Although suchconfiguration is provided for example, it should be understood that thehook 114 and the latch 115 may be attached to the opposite componentdescribed above or that many other mechanisms may be employed to achievesuch positive engagement of the bearing disk 60 and the drive disk 34 atlimiting positions of the ramp bearings 62.

[0083] A further improvement of certain embodiments over previousdesigns is a drive disk 34 having radial spokes (not separatelyidentified), reducing weight and aiding in assembly of the transmission100. In a certain embodiment, the drive disk 34 has three spokesequidistant from each other that allow access to, among othercomponents, the hook 114 and the latch 115.

[0084] Another improvement of certain embodiments includes the use ofthreads 35, such as acme threads, to move the drive disk 34 axially whenthere is relative rotational movement between the drive disk 34 and thebearing disk 60. Referring to the embodiment illustrated in FIG. 1, athreaded male screw 35 may be threaded into a set of female threads 37,or a nut 37, in the bore of the drive disk 34. This allows the drivedisk 34 to disengage from the speed adjusters 1 when the drive disk 34ceases to provide input torque, such as when coasting or rolling inneutral, and also facilitates providing more or less axial force againstthe speed adjusters 1. Furthermore, the threaded male screw 35 is alsodesigned to transmit an axial force to the drive disk 34 via the set offemale threads 37.

[0085] Yet another improvement of certain embodiments over pastinventions consists of an improved method of shifting the transmissionto higher or lower transmission ratios. Again, referring to theembodiment illustrated in FIG. 1, this method can be accomplished byusing a threaded rod 10, including, for example, a left hand threadedworm screw 11 and a corresponding right hand threaded shifting tube 50,or sleeve, that operates remotely by a cable 53 or remote motor or otherremote means. Alternatively, left-handed threads can be used for boththe worm screw 11 and the shifting tube, or a non-threaded shifting tube50 could be used, and any combinations thereof can also be used asappropriate to affect the rate of shifting the transmission 100 withrespect to the rate of rotation of the shifting tube 50. Additionally, aconical spring 55 can be employed to assist the operator in maintainingthe appropriate shifting tube 50 position. The worm screw 11 ispreferably mated with a threaded sleeve 19 so as to axially align thesupport member 18 so that when the worm screw 11 is rotated the supportmember 18 will move axially.

[0086] Another improvement of some embodiments over past inventions isthe disengagement mechanism for the transmission 100. The disengagementmechanism allows the input sprocket, pulley, or gear 38 to rotate inreverse, and also allows the transmission 100 to coast in neutral bydisengaging the drive disk 34 from the speed adjusters 1.

[0087] The foregoing description details certain embodiments of theinvention. It will be appreciated, however, that no matter how detailedthe foregoing appears in text, the invention can be practiced in manyways. As is also stated above, it should be noted that the use ofparticular terminology when describing certain features or aspects ofthe invention should not be taken to imply that the terminology is beingre-defined herein to be restricted to including any specificcharacteristics of the features or aspects of the invention with whichthat terminology is associated. The scope of the invention shouldtherefore be construed in accordance with the appended claims and anyequivalents thereof.

What is claimed is:
 1. A continuously variable transmission having alongitudinal axis, comprising; a plurality of speed adjusters, eachhaving a tiltable axis of rotation, and each speed adjuster locatedradially outward from the longitudinal axis; a drive disk annularlyrotatable about the longitudinal axis and having a first side contactinga first point on each of the speed adjusters and having a second sidefacing away from the speed adjusters; a driven disk annularly rotatableabout the longitudinal axis and contacting a second point on each of thespeed adjusters; a generally cylindrical support member annularlyrotatable about the longitudinal axis and contacting a third point oneach speed adjuster; a set of perimeter ramps annularly rotatable aboutthe longitudinal axis and adapted to provide rotational and axial forceto the second side of the drive disk; and a set of central rampsannularly rotatable about the longitudinal axis and adapted to transmittorque to the perimeter ramps.
 2. The transmission of claim 1, furthercomprising: a nut formed by internal threads that are mounted near thecenter portion of the drive disc; and a screw in operable contact withthe central ramps and adapted to fit within and mate with the nut,wherein the screw and nut transfer torque from the central ramps to thedrive disc and apply axial force to the drive disc.
 3. The transmissionof claim 2, wherein the central ramps further comprise a set of centralscrew ramps and a complimentary and mating set of central drive shaftramps, wherein the central ramps are adapted to distribute axial forcegeneration between the screw and nut and the perimeter ramps.
 4. Thetransmission of claim 3, further comprising a generally cylindricaldrive shaft that is rotatable about the longitudinal axis and has afirst end to which the central drive shaft ramps are operably attachedand a second end extending out of the transmission that is adapted toreceive torque input to the transmission.
 5. The transmission of claim4, wherein the second end of the drive shaft is adapted to receive inputtorque from a sprocket of a bicycle.
 6. The transmission of claim 4,wherein the second end of the drive shaft is adapted to receive inputtorque from an automobile engine.
 7. The transmission of claim 4,wherein the second end of the drive shaft is adapted to receive inputtorque from a motorcycle engine.
 8. The transmission of claim 4, whereinthe second end of the drive shaft is adapted to receive input torquefrom a tractor engine.
 9. The transmission of claim 4, wherein thesecond end of the drive shaft is adapted to receive input torque from anelectric motor.
 10. The transmission of claim 4, wherein the output discis a hub adapted to at least partially encapsulate the speed adjustersand drive disk.
 11. The transmission of claim 4, wherein the screw andnut comprise a first axial force generator and the perimeter rampscomprise a second axial force generator.
 12. The transmission of claim11, wherein the axial force component produced by each of the first andsecond axial force generators varies as the transmission is shifted. 13.The transmission of claim 11, wherein the axial force is larger in a setof low transmission ratios than in a set of high transmission ratios fora corresponding change in transmission ratio.
 14. The transmission ofclaim 11, wherein the first and second axial force generators shareproduction of the axial force to the drive disk.
 15. The transmission ofclaim 11, wherein the first and second axial force generators produceaxial force separately, and wherein the first axial force generatorproduces substantially all of the axial force applied to the drive diskin a high transmission ratio, and the second axial force generatorproduces substantially all of the axial force applied to the drive diskin a low transmission ratio.
 16. The transmission of claim 11, whereinthe screw has a face that faces the speed adjusters and has an annularbearing race thereon adapted to receive thrust from a thrust bearing tobias the screw in a direction away from the speed adjusters.
 17. Thetransmission of claim 15, wherein the set of central ramps is adapted toadjust the amount of axial force produced by each of the first andsecond axial force generators.
 18. A transmission having a longitudinalaxis, comprising: a plurality of spherical speed adjusters each havingan axis of rotation, each speed adjuster adapted to rotate about itsaxis and each speed adjuster contacted at a first point by a drive discat a second point by a driven disc and at a third point by a centralsupport member; at least two axial force generators adapted to provide acontact force between the drive disc, the driven disc, the supportmember and the plurality of speed adjusters; and a distributor adaptedto distribute the amount of axial force generated between each of the atleast two axial force generators according to an amount of torqueapplied to the distributor.
 19. A method for controlling the ratio of arate of rotation of a drive disc to that of a driven disc, comprising:aligning the drive disc and driven disc coaxially along a longitudinalaxis; distributing a plurality of spherical speed adjusters about thelongitudinal axis between the input and output disc; generating an axialforce with at least two axial force generators; applying the axial forceto the drive disc in order to create a contact between the speedadjusters and each of the drive disc and the driven disc; and adjustingthe amount of axial force generated by each of the at least two axialforce generators depending on a magnitude of torque to be transferredfrom the drive disc to the plurality of speed adjusters.
 20. The methodof claim 19, further comprising disengaging the axial force when themagnitude of torque falls below a particular amount for any given rateof rotation of the driven disc.